Microsoft agreed to pay Norway's Opera Software $12.75 million to head off a threatened lawsuit over code that made some Web pages on MSN look bad in certain versions of Opera's Web browser, CNET News.com has learned. Opera disclosed the payment last week in a terse press release that omitted other details, including the name of the settling party and the nature of the dispute.

But a source indicated that the payment came from Microsoft in order to close the books on a clash over obscure interoperability problems. On at least three separate occasions, Opera has accused Microsoft of deliberately breaking interoperability between its MSN Web portal and various versions of the Opera browser--charges that the software giant has repeatedly denied. A Microsoft representative said the company does not comment on rumors.